From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 246A8C4360F for ; Tue, 2 Apr 2019 15:53:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E99ED2084B for ; Tue, 2 Apr 2019 15:53:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730579AbfDBPxK (ORCPT ); Tue, 2 Apr 2019 11:53:10 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:53534 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725889AbfDBPxK (ORCPT ); Tue, 2 Apr 2019 11:53:10 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CD894374; Tue, 2 Apr 2019 08:53:09 -0700 (PDT) Received: from localhost (unknown [10.37.6.20]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3793F3F721; Tue, 2 Apr 2019 08:53:09 -0700 (PDT) Date: Tue, 2 Apr 2019 16:53:07 +0100 From: Andrew Murray To: Suzuki K Poulose Cc: linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, Marc Zyngier , linux-kernel@vger.kernel.org, Zenghui Yu , kvmarm@lists.cs.columbia.edu Subject: Re: [PATCH] kvm: arm: Skip stage2 huge mappings for unaligned ipa backed by THP Message-ID: <20190402155307.GE53702@e119886-lin.cambridge.arm.com> References: <1554203176-3958-1-git-send-email-suzuki.poulose@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1554203176-3958-1-git-send-email-suzuki.poulose@arm.com> User-Agent: Mutt/1.10.1+81 (426a6c1) (2018-08-26) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 02, 2019 at 12:06:16PM +0100, Suzuki K Poulose wrote: > With commit a80868f398554842b14, we no longer ensure that the > THP page is properly aligned in the guest IPA. Skip the stage2 > huge mapping for unaligned IPA backed by transparent hugepages. > > Fixes: a80868f398554842b14 ("KVM: arm/arm64: Enforce PTE mappings at stage2 when needed") > Reported-by: Eric Auger > Cc: Marc Zyngier > Cc: Chirstoffer Dall > Cc: Zenghui Yu > Cc: Zheng Xiang > Tested-by: Eric Auger > Signed-off-by: Suzuki K Poulose > --- > virt/kvm/arm/mmu.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c > index 27c9583..4a22f5b 100644 > --- a/virt/kvm/arm/mmu.c > +++ b/virt/kvm/arm/mmu.c > @@ -1412,7 +1412,9 @@ static bool transparent_hugepage_adjust(kvm_pfn_t *pfnp, phys_addr_t *ipap) > * page accordingly. > */ > mask = PTRS_PER_PMD - 1; > - VM_BUG_ON((gfn & mask) != (pfn & mask)); > + /* Skip memslots with unaligned IPA and user address */ > + if ((gfn & mask) != (pfn & mask)) > + return false; > if (pfn & mask) { > *ipap &= PMD_MASK; > kvm_release_pfn_clean(pfn); > -- > 2.7.4 I was able to reproduce this issue on v5.1-rc3 on a SoftIron Overdrive 1000 (AMD Seattle (Rev.B1)) with defconfig+ARM64_64K_PAGES with: qemu-system-aarch64 -cpu host -machine type=virt,accel=kvm -nographic -smp 4 -m 4096 -kernel /boot/vmlinuz-4.9.0-7-arm64 --append "console=ttyAMA0 default_hugepagesz=2M hugepages=256" The 'default_hugepagesz=2M hugepages=256' had no effect on the reproducibility, however the guest only intermittently failed to boot. Applying the above patch fixed this and the guest boots every time. Tested-by: Andrew Murray Thanks, Andrew Murray > > _______________________________________________ > kvmarm mailing list > kvmarm@lists.cs.columbia.edu > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm